Cloud computing enables hardware and software resources to be accessed over the Internet. IaaS is one of the cloud services which offers computing power on demand by providing virtual machines to the consumers. As the number of users increase, IaaS cloud generates more number of VM images and snapshots. Hence, it is necessary to optimally utilize the storage space of IaaS to improve the performance. A well-known deduplication technique is used for efficient utilization of storage space. Since, the metadata generated is huge with the deduplication technique, it can only be maintained in the hard disk. Hence, prefetching a suitable subset of metadata is essential to improve I/O throughput. Thus, the objective of this paper is to compare the effectiveness of the similarity and locality indexing mechanisms with a common set of performance metrics to suggest a better indexing mechanism for IaaS cloud.